The intense commercialization o f metallocene polyolefin catalysts has led to widespread interest in the design of non-metallocene, homogeneous catalysts. This field is more than an academic curiosity as new, non-metallocene catalysts may provide an easier pathway to currently available products and may also provide product and process opportunities which are beyond the capability of metallocene catalysts. In addition, certain non-cyclopentadienyl ligands may be more economical due to the relative ease of synthesis of a variety of substituted analogs.
Thus there is a need in the art for new novel olefin polymerization catalysts. U.S. Ser. No. 09/103,620 discloses the use of transition metal compounds comprising bidentate ligands containing pyridine or quinoline moieties and mixtures thereof with activators to polymerize olefins. In particular [[1-(2-Pyridyl)N-1-Methylethyl]-[1-N-2, 6-Diisopropylphenyl Amido]][2-Methyl-1-Phenyl-2-Propoxy] Zirconium Dibenzyl is combined with modified methyl alumoxane in the gas phase to produce ethylene hexene copolymers.
We have found that the systems in U.S. Ser. No. 09/103,620 U.S. Pat. No. 6,103,657 can be modified by the direct addition of an additive to produce bimodal products from a single catalyst.
For U.S. purposes the following references are mentioned: U.S. Pat. Nos. 4,845,067; 4,999,327; JP 1126111; U.S. Pat. No. 4,508,842; and UK 1015054.